Analog Devices Inc./Maxim Integrated MAX6385XS18D4-T

Overview

MAX6385XS18D4-T from Maxim Integrated is a push-pull active-high microprocessor supervisory circuit with factory-set 1.8V reset threshold, 1120ms VCC reset timeout, and debounced manual reset input. It monitors single supply voltage in low-power embedded systems, consumes only 3μA at 1.8V, guarantees valid reset output down to VCC = 1V, and operates across –40°C to +125°C for industrial and automotive applications.

For engineers reviewing the MAX6385XS18D4-T datasheet, MAX6385XS18D4-T pinout, MAX6385XS18D4-T application, or MAX6385XS18D4-T equivalent, key selection criteria include its active-high push-pull output logic, 1.8V ±2.5% threshold accuracy over temperature, 1120ms minimum VCC reset timeout, manual reset input with internal pullup, and 4-pin SC70 package compatibility with space-constrained PCB layouts.

Technical Context

The MAX6385XS18D4-T implements a precision bandgap-based voltage comparator to monitor VCC against a fixed 1.8V threshold, with ±2.5% accuracy over –40°C to +125°C. Its internal timer generates a guaranteed-minimum 1120ms reset assertion after VCC recovers above threshold.

A dedicated MR input provides TTL/CMOS-compatible manual reset initiation with 1μs minimum pulse width and 100ns glitch rejection. The device uses BiCMOS process technology and features negative-going VCC transient immunity up to 35µs at 100mV overdrive.

Key Specifications

Pinout & Package

MAX6385XS18D4-T is housed in a RoHS-compliant 4-pin SC70 package (outline 21-0098, land pattern 90-0187), measuring 1.25mm × 1.25mm × 0.95mm with gull-wing leads.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor reset applications.

Compared with MAX6326XR18D4+T and TPS3123E18DBVR, the MAX6385XS18D4-T uniquely combines active-high push-pull output, integrated MR input with internal pullup, and industry-leading 3μA supply current - making it optimal for space- and power-constrained applications requiring both automatic and manual reset capability.

Availability

MAX6385XS18D4-T is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, medical wearable sensors, smart energy meters, and battery-powered instrumentation requiring stable component supply with long-term lifecycle support.

Supply support for MAX6385XS18D4-T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated, now part of Analog Devices, designs precision analog, mixed-signal, and power management ICs for industrial, automotive, communications, and computing markets.

The MAX6381–MAX6390 family delivers low-power, high-accuracy microprocessor supervisory circuits optimized for single- and dual-voltage systems in harsh environments, with emphasis on extended temperature operation and minimal board space.

FAQ

What is the exact reset threshold voltage of MAX6385XS18D4-T and how accurate is it over temperature?

The MAX6385XS18D4-T has a factory-set reset threshold of 1.8V with ±2.5% accuracy over the full operating temperature range of –40°C to +125°C. This specification is guaranteed by design and ensures reliable brownout detection without requiring external calibration. At +25°C, the threshold is typically 1.8V ±1.5%, tightening to ±2.5% across extremes. The MAX6385XS18D4-T maintains this accuracy due to its precision bandgap reference and low-tempco comparator architecture.

Does MAX6385XS18D4-T support manual reset, and what are the electrical requirements for the MR pin?

Yes, the MAX6385XS18D4-T includes a debounced manual reset input (MR) with an internal 63kΩ pullup resistor to VCC. To assert reset, MR must be driven below 0.3×VCC (e.g., <0.54V at VCC = 1.8V). The input accepts TTL/CMOS logic levels and rejects glitches shorter than 100ns. Minimum pulse width is 1μs. When unused, MR may be left floating or tied to VCC; no external components are required for basic operation.

What is the guaranteed minimum reset timeout period for MAX6385XS18D4-T, and does it vary with temperature?

The MAX6385XS18D4-T guarantees a minimum VCC reset timeout of 1120ms after VCC rises above the 1.8V threshold. This value is specified at TA = –40°C to +125°C and shows less than ±1.5% variation across temperature, as confirmed by normalized timing plots in the datasheet. The timeout is generated by an internal RC timer and is independent of supply voltage within the 1.0V to 5.5V operating range.

Can MAX6385XS18D4-T operate reliably when VCC drops below 1.8V, and down to what voltage does it maintain valid reset output?

Yes, the MAX6385XS18D4-T is guaranteed to maintain valid reset output state down to VCC = 1.0V. Below 1.8V, the device continues asserting reset until VCC recovers above threshold and the 1120ms timeout expires. Its push-pull output remains functional - sinking 80μA at VCC ≥ 1.0V and sourcing 150μA at VCC ≥ 1.8V - enabling robust operation during deep brownout conditions where many competitors fail.

What package type and footprint does MAX6385XS18D4-T use, and are land patterns available?

The MAX6385XS18D4-T is supplied in a 4-pin SC70 package (outline number 21-0098, land pattern 90-0187), measuring 1.25mm × 1.25mm × 0.95mm. This RoHS-compliant, lead-free package uses gull-wing leads compatible with standard reflow soldering. Official land patterns and solder mask specifications are published by Maxim Integrated and available at maximintegrated.com/packages; the recommended footprint accommodates thermal relief and manufacturability for high-yield assembly.